Peripheral blood and semen are principle sources of transmission of many human pathogens, including Human Immunodeficiency Virus (HIV), Human T Cell Leukemia Viruses (HTLVs), hepatitis B and hepatitis C in addition to the more widely recognized sexually transmitted diseases such as gonorrhea, syphilis and chlamydiasis. Blood samples are frequently used to diagnose these diseases, principally by an automated laboratory test which identifies pathogen-specific proteins or antibodies contained in serum samples. Semen is rarely used as a diagnostic fluid unless the individual is being evaluated for fertility because of the relative logistical ease of obtaining blood samples and the large reference base for normal blood values, in contrast to the relative difficulty in obtaining and evaluating semen samples and the lack of a reference base for semen pathogens. Thus, even diseases of male reproductive tract organs directly involved with semen production (e.g. carcinoma of the prostate) are rarely, if at all, diagnosed or evaluated by analyzing semen samples.
Current laboratory safety practices (termed Universal Precautions) include wearing gloves, masks, goggles and laboratory coats when opening or handling blood tubes, but no general scheme for pathogen inactivation prior to blood handling at a testing facility is currently available. Universal Precautions are the only andrology laboratory safety practices currently available for the safe handling of semen samples.
in general, two types of blood samples are routinely obtained by venipuncture in clinical blood drawing stations: (1) samples intended to yield cell-free serum or plasma for antigen or antibody measurements and (2) samples in which coagulation is blocked by anticoagulants such as heparin or chelating agents (salts of citric acid or ethylenediaminetetraacetic acid, EDTA) for evaluation of peripheral blood cells. Anticoagulated blood samples are used for evaluation of cellular blood components such as platelets, red blood cells and the various classes of leukocytes. Leukocytes are differentiated by morphology (either by automated instrument or by a technician looking at a smear in a microscope), by specific surface antigens (such as the CD4 or CD8 receptors on some lymphocyte subtypes) or by nuclear DNA content (as assessed, for example, by flow cytometry).
Semen generally is collected by spontaneous ejaculation into a condom during intercourse or into a sterile laboratory container following masturbation. To discover possible causes of infertility or to verify vasectomy or vasectomy reversal, ejaculated semen is evaluated in andrology laboratories for cell type and concentration and for seminal fluid composition with respect to typical semen components (e.g., zinc, fructose) and the possible presence of anti-sperm antibodies and pathogens. Seminal fluid also contains leukocytes and other cells such as prostate and seminal vesicle cells in addition to mature and immature germ cells. Automated sample analysis is not currently available for semen samples. Accordingly, semen analysis is labor intensive, requiring substantial sample handling and processing by laboratory personnel.
In summary, all aspects of handling blood and semen samples expose health care personnel to potentially infectious pathogens. In addition to the potential for infection, blood and serum samples pose unique problems for the accurate and sensitive analysis of clinically-relevant analytes. For example, although amplification of selected DNA sequences by polymerase chain reaction (PCR) is a powerful diagnostic tool for the identification of genetic mutations, wide clinical application of the technique to the analysis of biological fluids for detection of infectious agents has been delayed due to a number of factors, including problems inherent in collecting and transporting infectious samples and the complexity and expense of the amplification technique. Thus, although a number of publications have reported using the polymerase chain reaction to detect single copies of human immunodeficiency virus (HIV) genes in isolated DNA, PCR amplification of DNA in HIV-infected peripheral blood samples requires leukocyte isolation (e.g., by centrifugation techniques, such as Ficol1 gradients) and/or cellular DNA purification (e.g., using reagents such as guanidium isothiocyanate) prior to amplification and detection of HIV-specific DNA sequences. Such extensive sample preparation reportedly is necessitated by the inhibitory effect of blood components (e.g., hemoglobin) on the amplification reaction. As a result, application of the PCR method to the analysis of biological fluid samples increases the risk of transmission of infectious agents to laboratory personnel.
The wide spread application of PCR for analyzing biological fluid samples additionally has been delayed because of the capital expense associated with creating and maintaining an adequately-equipped laboratory for practising amplification on a biological fluid sample, i.e., the laboratory must be equipped for pathogen containment, DNA purification and radiolabeled oligonucleotide probes in order to achieve the sensitivity necessary to detect single copies of provirus in a background of large copy numbers of cellular DNA.
In view of the foregoing, there is still a need for methods for safely handling, transporting and analyzing potentially infectious biological fluid samples. Such methods would permit the disinfection of infectious agents contained in the biological fluid sample at the time of sample collection, thereby minimizing the risk of transmission to laboratory personnel.